1. Field of the Invention
The present invention relates to a liquid discharge head that discharges a desired liquid by the creation of bubbles by the application of thermal energy that acts upon the liquid, and the method of manufacture therefor. More particularly, the invention relates to a liquid discharge head provided with a movable member which is displaceable by the utilization of created bubbles, and to the method of manufacture therefor as well. In this respect, the term xe2x80x9crecordingxe2x80x9d in the description of the present invention means not only the provision of images having characters, graphics, or other meaningful representation on a recording medium, but also, the provision of those images that do not present any particular meaning, such as patterns, on it.
2. Related Background Art
There has been known the so-called bubble jet recording method, which is an ink jet recording method whereby to form images on a recording medium by discharging ink from discharge ports using acting force exerted by the change of states of ink accompanied by the abrupt voluminal changes (creation of bubbles), and to form images on a recording medium by the discharged ink that adheres to it. For the recording apparatus that uses the bubble jet recording method, it is generally practiced to provide, as disclosed in the specifications of Japanese Patent Publication No. 61-59911 and Japanese Patent Publication No. 61-59914, the discharge ports that discharge ink, the ink paths conductively connected to the discharge ports, and heat generating members (electrothermal converting means) arranged in each of the ink paths as means for generating energy for discharging ink.
In accordance with such recording method, it is possible to record high quality images at high speeds with a lesser amount of noises. At the same time, the head that executes this recording method makes it possible to arrange the discharge ports for discharging ink in high density, with the excellent advantage, among many others, that images are made recordable in high resolution, and that color images are easily obtainable by use of a smaller apparatus. In recent years, therefore, the bubble jet recording method is widely utilized for office equipment, such as a printer, a copying machine, a facsimile equipment. Further, this method is utilized for an industrial system, such as a textile printing system.
Under the circumstances, some of the inventors hereof have made ardent studies, while giving attention again to the principle of liquid discharges, in order to provide a new liquid discharge method that utilizes bubbles, as well as a head and others used for such method that has not been obtainable in accordance with the conventional art, and have taken out a patent as applied in Japanese Patent Application No. 8-4892 and some others.
The patent disclosed in the Japanese Patent Application No. 8-4892 and some others is a technique to positively control bubbles by the arrangement of the positional relationship between the fulcrum and the free end of a movable member in a liquid flow path so as to make the relationship such that the free end is positioned on the discharge port side, namely, on the downstream side, and also, by the arrangement of the movable member to face a heat generating member or a bubble generating area.
With the above-mentioned newest liquid discharge head and others provided on the basis on the restudied discharge principle, it becomes possible to obtain the synergic effect of the created bubble and the movable member to be displaced thereby. As a result, liquid in the vicinity of the discharge port can be discharged efficiently to enhance the discharge efficiency significantly as compared with the conventional discharge methods and heads of bubble jet type.
In this respect, the conventional liquid discharge head is structured with the movable member and the base unit thereof formed as individual bodies, respectively, as described above. Then, the movable member is positioned to the elemental substrate. After that, the movable member is bonded to the base unit by the application of gold bonding or adhesive agent.
In recent years, the materialization of a more precise liquid discharge head has been in demand. To this end, it becomes necessary to make the interior of each liquid flow paths more precise.
However, since the movable member and the base unit thereof are formed individually for the liquid discharge head described above, there is a problem that it is difficult to implement making each of the liquid flow paths more precise due to the positional relationship between the movable member and the base unit thereof.
With a view to solving the problems of the conventional techniques as discussed above, the present invention is designed. It is an object of the invention to provide a method for manufacturing a liquid discharge head whereby to make the interior of each liquid flow path finer in higher precision.
In order to achieve the objects described above, the method for manufacturing liquid discharge heads of the present invention, which is provided with discharge ports for discharging liquid; liquid flow paths communicated with the discharge ports for supplying liquid to the discharge ports; a substrate having heat generating members for creating bubbles in liquid; and movable members facing the heat generating members, each being arranged in each liquid flow path, having the free end on the discharge port side with a specific gap with the heat generating member, comprises the steps of forming the boundary layer used for providing a gap between the movable member and the substrate above the heat generating member on the substrate; of laminating the movable member on the boundary layer so as to position the free end above the heat generating member, at the same time fixing the movable member on the substrate; and of forming the gap between the movable member and the heat generating member by use of the boundary layer.
Also, the liquid discharge head of the present invention comprises a plurality of discharge ports for discharging liquid; a plurality of liquid flow paths communicated with each of the discharge ports to supply liquid to each of the discharge ports; a substrate provided with heat generating members for creating bubbles in liquid; movable members arranged in the plural liquid flow paths, each having the free end on the discharge port side to face the heat generating member; and pedestal portions formed on the substrate for supporting the movable members. Then, the movable member has the property of being curved by heat, and the portion corresponding to the movable range is separated from the substrate by the application of heat.
Also, the liquid discharge head of the present invention comprises a plurality of discharge ports for discharging liquid; a plurality of liquid flow paths communicated with each of the discharge ports to supply liquid to each of the discharge ports; a substrate provided with heat generating members for creating bubbles in liquid; movable members arranged in the plural liquid flow paths, each having the free end on the discharge port side to face the heat generating member; and pedestal portions formed on the substrate for supporting the movable members. Then, the portion of the movable member corresponding to the movable range is separated from the substrate by means of the inner stress and the function of the releasable layer formed on the substrate.
Also, the liquid discharge head of the present invention comprises a plurality of discharge ports for discharging liquid; a plurality of liquid flow paths communicated with each of the discharge ports to supply liquid to each of the discharge ports; a substrate provided with heat generating members for creating bubbles in liquid; movable members arranged in the plural liquid flow paths, each having the free end on the discharge port side to face the heat generating member; and pedestal portions formed on the substrate for supporting the movable members. Then, the portion of the movable member corresponding to the movable range is provided with a recessed part on the portion adjacent to the pedestal portion.
Also, the liquid discharge head of the present invention comprises discharge ports for discharging liquid; liquid flow paths communicated with each of the discharge ports to supply liquid to each of the discharge ports; a substrate provided with heat generating members for creating bubbles in liquid; and movable members arranged in the plural liquid flow paths, each having the free end on the discharge port side to face the heat generating member, and the free end being positioned on the downstream of the area center of the heat generating member. Then, the movable member is formed either one of silicon nitride, diamond, amorphous carbon hydride, and silicon oxide, and being incorporated on the substrate.
With the structure as described above, the movable portion of the movable member is separated from the substrate after the formation of the movable member on the substrate. Then, the movable member is incorporated in the liquid discharge head. As a result, there is no need for the process to position the movable member to the substrate as the member that functions as a different body, hence implementing arranging each interior of many numbers of the liquid flow paths finer in higher precision.
In this respect, the terms xe2x80x9cupstreamxe2x80x9d and xe2x80x9cdownstreamxe2x80x9d referred to in the description of the present invention are used as expression with respect to the flow direction of liquid from the supply source of liquid to the discharge port through the bubble generating area (or the movable member) or the structural direction thereof.
The term xe2x80x9cdownstream sidexe2x80x9d related to the bubble itself represents the portion of the bubble on the discharge port side, which mainly acts upon the discharge of droplet directly. More specifically, it means the downstream side of the above-mentioned flow direction or the structural direction with respect to the center of each bubble or the bubble that may be created on the area of the downstream side of the area center of a heat generating member.
The term xe2x80x9cseparation wallsxe2x80x9d referred to in the description of the present invention means, in a broader sense, the walls (which may include the movable member) which are provided to divide the bubble generating area and the area that is communicated with a discharge port directly on a broader sense, and this term means, in a narrower sense, those which divide the flow path that includes the bubble generating area and the liquid flow path which is communicated with the discharge port in order to prevent the mixture of liquids each residing in the respective areas.
Further, the term xe2x80x9cthe teeth of a combxe2x80x9d referred to in the description of the present invention means the configuration in which the fulcrum of the movable member is formed by a shareable member, and then, the front of the free end thereof is in a state of being released.